Yttrium borides

MO2B5 dimolybdenum pentaboride [12007-97-5] ">2100 YB32 yttrium boride (1 12) [12046-90-1] 2200, d... 

Gmelin L, et al. (1980, 1988, 1990) Handbook of inorganic and organometallic chemistry. No 39, Cosmochemistry, Yttrium Borides, Coordination Compounds, Springer-Verlag, Berlin. 

Erbium and yttrium borides are used for lining solar panels. 

Boron phases with formulas MB50, and MB,00 (M = Y, Sm, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu, Th and Pu) are the same cubic phase from x-ray powder data , with the Fm3c Sjpace group. Single crystals of yttrium and thorium borides lead to the formula The MB lattice constant data are given in Table 1. 

It has been reported that ScBi2 has a tetragonal modification of the UBi2-type structure with lattice parameters of a = 5.22 A and c = 7.35 A with the space group of I4/mmm (Hamada et al., 1993 Paderno and Shitsevalova, 1995). Due to the small size of scandium as compared to the other rare earth atoms, scandium phases have been observed to form anomalous higher boride structures compared to the heavy lanthanides and yttrium, as will be discussed later in Sections 9 and 11. Small amounts of metal replacement for Sc in Sci xMxBi2 (x as small as 0.1, M = Y, Tm, Lu) have been reported to stabilize the structure in the normal cubic UBi2-type. 

The lanthanides are also examples of electropositive metals that form boron-ricii borides having boron subnetworks constructed from B12 icosahedra. An example of an extremely boron-ricii metal boride is YBee- The structure of YBee is very complicated with a unit cell containing approximately 24 yttrium atoms and 1584 boron atoms. The majority of the boron atoms (1248 = (8)(156)) are contained in 13-icosahedron units of 156 atoms each. In each 13-icosahedron unit a central B12 icosahedron is surrounded by 12 icosahedra leading to a Bise icosahedron of icosahedra . The remaining boron atoms are statistically distributed in channels that result from the packing of the 13-icosahedron units and from nonicosahedral cages that are not readily char-... 

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